1. Field of the Invention
The present invention relates to the production of separable slide fasteners, and more particularly to a method of attaching parts of a separable bottom end assembly to a continuous slide fastener chain.
2. Description of the Prior Art
Japanese Patent Publication (Tokkosho) No. 49-44243 discloses an automatic finishing apparatus for separable slide fasteners, as reillustrated here in FIG. 4, in which publication an insertion pin 8b (FIG. 5A) and a box pin 8a (with a box 8c) (FIG. 6A), both in the shape of a channel, of a separable bottom end assembly are threaded onto the respective leading element-free end portions 4a, 4a of a pair of uncoupled continuous slide fastener stringers 2, 2 in an endwise direction, i.e. longitudinally from one of opposite end openings of the respective pin, as shown in FIGS. 5A and 6A. Each pin 8a, 8b is then fixedly secured to the element-free end portion 4a as compressed into a final shape (FIGS. 5B and 6B) therearound by means of a respective holder or punch B, C (FIG. 4). A common problem with this prior art method is that because of smallness of the end openings of the pin, it is difficult or impossible to mount the pin correctly in a required position on the leading element-free end portion, especiallly if the latter is in objectionably bulged or otherwise deformed condition. Further, this inaccurate and insufficient threading would be a cause for possible misoperations in various subsequent progressive finishing stages of the production, thus resulting in inadequate quality products.